Central Asia

by Heyer Évelyne - published on 9 January 2009, updated on 8 March 2013 at 12:29

Since 2001 we have been sampling several populations in Central Asia. Our field work include DNA sampling, linguistic data and ethnological survey. Using these data we focus on population history of the region, impact of social organisation on genetic dievrsity, genetic linguistic distances and adaptation to diet (NAT2, Lactase Pesristency, Diabetis Type II).

Population History
Using mitochondrial data from the populations we have sampled and data from litterature, we show a colonisation process during the paleolithic from East to West in Eurasia. (Chaix, 2008)

Social organisation
Our project highlights the differences in genetic diversity between ethnic groups belonging to the Turkish language family and those belonging to Indo-European language family. . In particular, we focused on the impact on social organisation on the genetic diversity of these populations since Turkish populations are organised in patrilineal descent groups (lineages, clans and tribes see Chaix,2004), with rules of exogamy, whereas Indo-European populations are organised in families, with rules of endogamy. We shown that Turkish populations, but not Indo-European populations, exhibited a significant loss of intra population genetic diversity for their Y chromosome (inherited from father to son), as a result of the dynamics of their patrilineal descent groups and significant genetic differences among populations regardless of their ethnic group considered. We also shown that Indo-European populations are differentiated for their mitochondrial DNA (transmitted from mother to daughter), whereas Turkish populations are not differentiated even at the ethnic groups level. (Chaix, 2007) This observation is likely to result from the different ways of exchanging spouses among populations, with fewer exchanges between Tajik populations than between Turkish populations. Using autosomal and X markers we also showed that effective population size of female is singificantly larger than for male in Turco-Mongol populations (Segurel, 2008)

Linguistic and genetic diversity
Using autosomal neutral markers, we further observe the differences between Turkish groups and Indo-European groups, with the Turkish group being more closely related to eastern Eurasia, and the Indo-European being closely related to Europe and Pakistan. These autosomal markers also enable us to identify several populations who have gone through a language shift.
Regarding linguistic data, we have been able to design a field study and methodology that enable the computation of linguistic distances. The correlation between linguistic and genetic distances is in process.

Adaptation to diet
These linguistic groups also have differences in life style that have had an impact on the evolution of their genes involved in the detoxication (NAT2 see Magalon, 2008) and genes involved in alimentation (Lactase persistency). We are now focusing on gene involved in Diabetis typeII
NUTGENEVOL Project